package luogu.editor;

import java.util.*;

public class p8780 {
    // 从周一开始.周一至周五每天做 a 道题目，周六和周日每天做 b 道题目。
    // 请你帮小明计算，按照计划他将在第几天实现做题数大于等于 n 题?
    // 输入一行包含三个整数 a,b 和 n.
    // 输出一个整数代表天数。
}

class Main {
    public static void main(String[] args) {
        int result = 0;
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        int a = Integer.parseInt(s.split(" ")[0]);
        int b = Integer.parseInt(s.split(" ")[1]);
        int n = Integer.parseInt(s.split(" ")[2]);
        int a5 = a * 5;
        int b2 = b * 2;
        int curr = 0;
        for (result = 0; curr < n; result += 7) {
            curr = a5 + b2;
        }
        int diff = curr - n;
        if (diff > a5) {
            diff = diff - a5;
            result += 5;
            for (int i = 0; i < 2; i++) {
                if ((diff -= b) > 0) {
                    result++;
                }
            }
        } else {
            for (int i = 0; i < 5; i++) {
                if ((diff -= a) > 0) {
                    result++;
                }
            }
        }
    }
}
